Compressor unit



June-15,1948. R. B. WESTON I 2,443,286-

COMPRESSOR UNIT Filed Nov; 25, 1946 56 i cw are: conn- $4 To Mmmua \huns Am FIZCEZING unrr or CbMPRIS l 52 50 Hum Panama 2:::.:;";:1-="" INVENTOR. 25

BY $419M J1. M

Patented June 15, 1948 NITED sures PATENT orncs COIHPRESQOB UNIT Ralph B. Weston, Los Angeles, Calif. Application NovemberZS, 1948, Serial No. 712,105

2 Claims. 1

' pump, a pressure responsive mechanism acting to switch on the motor or disconnect the engine which then merely idles, when the pressure in the tank exceeds a predetermined maximum value, and to switch on the motoror clutch in the engine and open the engine throttle when the air pressure in the tank falls below a predetermined minimum value.

Since the minimum value will still .be quite high in order to supply the equipment served by the storage tank, this constant, sudden starting against a heavy load causes undue wear of the engine or motor and may cause burning out of electric motors.

The general dbject of my invention is to provide a compressor system which will avoid the sudden imposition of relatively heavy loads on the power means driving the pump of the compressor,

The invention will be hereinafter described with specific reference to certain types of apparatus, but it is to be understood that the invention is not necessarily restricted to such apparatus.

An object of the invention is to provide a compressor unit including an auxiliary tank under reduced pressure connected in series with the main storage tank which is maintained at a higher pressure, the compressor pump being connected to said auxiliary tank and at each operation thereof by its driving means delivering air to the auxiliary tank until the pressure therein equals the pressure in the main tank, the air delivered by the pump thereafter entering the main tank until a predetermined pressure is reached and the pump is put out of operation.

A further object of the invention is to provide a compressor system provided with means whereby the back pressure against which the compressor works is reduced during the initial operation of the compressor.

Another object of the invention is to provide a compressor unit having a pressure tank connected to both the high pressure line and to the intake side of the compressor, a non-return valve being arranged in the high pressure line and a valve in the outlet to the low pressure line,

said valve being automatically closed during operation of the compressor and opened on the cutting out of the compressor to permit the pres- 5 sure in the tank to fall to that of the low pressure line.

A still further object of the invention is to provide a unit which will operate to relieve the load on the motor of a compressor when commencing to build up pressure,-which unit may be readily incorporated in existing compressor equipment. or can be built into compressor equipment during manufacture.

Still further features and objects of the invention will hereinafter appear from the following description, taken in conjunction with the accompanying drawings.

In the drawings:

(Fig. 1 is a side elevation of a compressor unit incorporating an auxiliary tank according to the invention;

Fig. 2 is a fragmentary view to a larger scale of the auxiliary tank and control valve shown in Fig. 1 and looking in the direction of the arrow 2 in that figure; and

Fig. 3 is a side elevation of a modified form of the invention adapted for incorporation in a domestic refrigerator.

In Fig, 1, the numeral l indicates a main air storage tank. A saddle I2 is welded, or otherwise mounted, on the top of the tank and provides a base for the electric motor i and air compressor IS, the motor serving to drive the air compressor by means of driving belt i8. An auxiliary air reservoir 20 of relatively small size, is connected to the outlet 22 of the compressor by a pipe 24 and to the main tank by pipe 25, provided with a non-return valve mounted in a fitting 28. The auxiliary tank is also pro- 0 vided with an automatic pressure relief valve.

generally indicated at 28, operated by an electromagnet 30 connected in parallel with the motor leads 32. The motor circuit is controlled by a pressure responsive switch 34 and by the 5 usual main switch.

In Fig. 2, the construction of the automatic pressure relief valve of the auxiliary tank and the arrangement of the electromagnet 30 is shown in detail. The pressure relief valve struc- 50 ture comprises a fitting 29 secured to tank 20 and drilled to provide a vent 36 through which the contents of the auxiliary tank may be vented to the atmosphere. The vent 36 is controlled. by

a small, mushroom valve 31 having an elongated to stem 31a guided in the vent. The electromagnet 30 is mounted on a bracket 38 secured to the fitting 29, the armature 50 being bolted to the bracket. A pole piece 52 is pivoted at $3 to the stationary portion of the armature, and is provided with a projecting lever arm Ml extending over the head of the. mushroom valve 37, and is so arranged that when the electromagnet is energized, the lever arm will beardown upon the head of the valve 8'I and securely .seal the vent 35. It will be obvious-that, instead of venting the auxiliary tank to atmospheric pressure, the valve ti may be loaded to maintain a desired minimum pressure in tank 20.

In this form of the invention, shown in Figs. 1 and 2, when the main switch 85 is closed, the motor will operate the compressor and simultaneously the electromagnet 30 will seal the vent 36 by holding the valve 31 On its seat, and air While I have described andillustrated preferred embodiments of my invention, it is to be understood that various changes and modifications may be made therein by those skilled in the art, without departingfrom the scope of the invention as intended to be defined by the appended claims.

claim:

1. A compressor unit including: a fluid com I pressor; means for driving said compressor; an

v means for holding said relief valve closed during under pressure from the compressor will flow into the auxiliary tank 20. When the pressure in tank becomes greater than that in the main tank 50, air will flow past the non-return valve in fltting 28 to the main tank until a predetermined maximum value is attained therein as determined by the setting of the pressure responsive switch 36. When the selected maximum pressure is attained, the switch 36 will be automatically operated to interrupt the motor circuit, and, since the electromagnet is in parallel with the motor, it will be de-energized and the pressure in the auxiliary tank 20 will be released.

Fig. 3 shows the apparatus of the invention arranged for use in a refrigerator. A main pressure tank is not required, the small tank 50 being directly connected to the out-put of the compressor (not shown), through inlet connection 5|. An outlet valve fitting 52 is connected to the usual metering valve and freezing coil of the refrigerator. A non-return valve (not shown) is provided in the outlet fitting 52-. A pressure relief valve fitting is mounted on the tank 50 to control a conduit 64 connecting the tank 50 with the in-take or low pressure side of the compressor. The conduit 64 is controlled by a valve 62 operated by an electromagnet 58 connected in parallel with the compressor motor circuit. The movable armature 60 of the electromagnet is operative, while energized during functioning of the compressor motor, to hold closed the valve 62, but when the motor is switched off, valve 62 is opened by the pressure in tank 50, enabling the tank to be brought to the pressure of the low pressure side of the refrigerant circuit. When the motor (not shown) is switched on, either initially, or automatically by the temperature of the refrigerator rising above a predetermined maximum, the outlet valve 62 is closed and gaseous or liquid refrigerant is forced by the compressor into the tank and through the outlet valve 52 into the refrigerating circuit. When the temperature of the refrigerator has been reduced to the desired value, the usual temperature responsive switching arrangement provided in refrigerators acts to interrupt the motor circuit, thereby de-energizing electromagnet 58 and again connecting tank 50 with the low pressure side of the system.

operation ofthe compressor and for releasing said relief valve holding means whenever the compressor is inoperative; and a main pressure tank, the outlet conduit from the auxiliary tank being connected to said main pressure tank.

2. A compressor unit including: a fluid compressor; an electric motor for driving said compressor; an auxiliary tank; a conduit connecting the compressor outlet with said auxiliary tank; an outlet conduit leading fluid under pressure from said auxiliary tank; a non-return valve in said conduit effective to prevent fluid under pres" sure from returning to said auxiliary tank through said outlet conduit; a relief valve venting fluid from said auxiliary tank; an electromagnet efi'ective while energized to hold said valve in closed position; an electrical operating circuit in which said motor and electromagnet are connected in parallel; a main pressure tank, the outlet conduit from the auxiliary tank connected to the compressor being connected to said main pressure tank; and a pressure responsive switch connected to said main pressure tank and effective when the pressure .in said tank reaches a predetermined value to switch off said electric motor and to de-energize said electromagnet to release the relief valve of the auxiliary tank, and when the pressure in said main pressure tank reaches a predetermined low value to switch on said motor and drive the compressor and to energize said electromagnet to close the relief valve, the fluid output of the compressor thereupon entering the auxiliary tank and building up pressure therein until it is sufilclent to enable the fluid to flow into i the main pressure tank.

' RALPH B. WESTON.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS 

